Photosensitizers in the fight against ticks: safranin as a novel photodynamic fluorescent acaricide to control the camel tick Hyalomma dromedarii (Ixodidae)

Abstract

Ticks transmit more pathogen species than any other group of blood-feeding arthropods worldwide, affecting humans, livestock, and companion animals. Hyalomma dromedarii is the predominant tick species infesting camels, and its effective control is of pivotal importance. In this research, we compared the phytoefficacy of safranin (SF), a fluorescent dye applied as an acaricide for the first time, to that of tetramethrin (TM) against engorged females of H. dromedarii through in vitro immersion bioassays. Furthermore, the effect of SF exposure was evaluated on the reproductive potential of surviving tick females. Different concentrations of SF (0.03, 0.06, 0.3, 1, and 4 % w:v) and TM (0.03, 0.13, 0.5, 2, and 4 %) were prepared in distilled water and administered to engorged females of H. dromedarii. SF-treated ticks were illuminated with a light source for 30 min post-treatment (PT). Photophysical properties of SF were studied, and the relative efficacy of the used light source and sunlight was calculated. Results showed that the minimum least concentration that causes 100 % acaricidal effect was 4 % PT with SF and TM, for 8 and 48 h, respectively. LC50 values 8 and 24 h PT were 0.08, 0.03 and 0.78, 0.20 %, respectively. Comparing LC50 and LC90 2 h PT, SF was 33 and 22 times more potent than TM. LT50 of 4 % SF and TM were 0.80 and 2.17 h, respectively. Treatment with the lowest concentrations of SF and TM induced reduction of the number of ovipositing females, eggs per female, ticks laying viable eggs, and hatched eggs. Overall, our results highlighted that SF is highly effective if compared to TM, allowing use to candidate it for the development of novel and safer acaricides.

Toxic and repellent activity of selected monoterpenoids (thymol, carvacrol and linalool) against the castor bean tick, Ixodes ricinus (Acari: Ixodidae)

“…On the other hand, the indiscriminate overuse of synthetic acaricides has led to concerns related to environmental pollution, non-target toxicity, and development of resistance in targeted tick populations (Naqqash et al, 2016). Therefore, environmentally friendly and cost-effective methods to protect humans and domestic animals from ticks would be welcome and attractive to global market of acaricides (Marimuthu et al, 2011(Marimuthu et al, , 2013Velayutham et al, 2012;Lupi et al, 2013;Rajakumar et al, 2013;Khater et al, 2016;Banumathi et al 2017).…”

Biological Control of Parasites

“…In addition to the previously mentioned biological control agents, parasites could also be controlled naturally through botanicals [163][164][165][166][167], photosensitizers [168,169], symbiotic [170], organic [171] and short-chain fatty acids [172]. Biological control approaches hold promise as the most suitable alternative to the chemical pesticides and are now a core component of IPM.…”

Natural Remedies in the Fight Against Parasites

“…The chemical methods are limited in their application, partly as a result of the rising resistance, environmental and health risks and the potential effect to non-target organisms. In addition to the previously mentioned biological control agents, parasites could also be controlled naturally through botanicals [163][164][165][166][167], photosensitizers [168,169], symbiotic [170], organic [171] and short-chain fatty acids [172]. Biological control approaches hold promise as the most suitable alternative to the chemical pesticides and are now a core component of IPM.…”